JP2006256339A - Manufacturing method for producing molded article of reclaimed thermoplastic resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recycled molded article which has no defects such as a sink, distortion, warp, or the like, furthermore which has the good dimension based on the variation of the molding shrinkage by recycling without changing the design and the molding condition of an injection molding apparatus at every recycling when a thermoplastic resin is recycled. <P>SOLUTION: The gas assisting method or the expansion injection molding method, wherein the pressure is effected on the molten molding material in the mold, is applied as the molding method. In this method, the molten molding material uniformly fills a mold cavity and the contraction strain by cooling is absorbed by the blowhole or the structure inside of the molded article to prevent the generation of the defects such as a sink, distortion, warp, or the like, and to dissolve the variation of the molding shrinkage characteristics by recycling, thereby the product having the good dimension can be obtained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a thermoplastic resin molded product again by recycling the thermoplastic resin molded product.

  Recently, recycling of waste plastic molded articles has been attracting attention. The recycling of the thermoplastic resin molded product is performed by pulverizing the waste product of the molded product and using the pulverized product as it is as a molding material, or by melting, extruding, cutting and pelletizing the pulverized product ( For example, see Patent Document 1).

  The recycled thermoplastic resin deteriorates due to heat applied during recycling, pelletization or molding, and physical properties such as impact resistance of the obtained recycled molded product are reduced. In particular, thermoplastic resins containing diene rubber, such as acrylonitrile / butadiene / styrene resin (ABS), high-impact polystyrene (HIPS), ABS and / or HIPS-modified polyphenylene ether (modified PPE) The unsaturated bond portion of the diene rubber is cleaved and the physical properties are remarkably deteriorated, and an olefin polymer such as polypropylene having a methyl group at the α-position has a polymer chain due to the electron repelling force of the methyl group. It is easy to cut and the physical properties are remarkably lowered.

  Therefore, recently, as a means for preventing deterioration in physical properties during recycling, it has been proposed to add a recycling improver during recycling. As the recycling improver, a rubber-like substance that is compatible with the thermoplastic resin is mainly used (see, for example, Patent Document 2).

International Publication No. 97/38838 Pamphlet International Publication No. 00/53384 Pamphlet

Injection molding is mainly applied to the production of thermoplastic resin molded articles.
However, as described above, the thermoplastic resin deteriorates due to the thermal history exerted by recycling, and the melt flow characteristics of the recycled thermoplastic resin change.

  The change in melt flow characteristics occurs even when the regenerated thermoplastic resin is added to a new thermoplastic resin in an amount of 1% by mass or more, particularly 5% by mass or more. Furthermore, even if a recycle improver is added to prevent a decrease in physical properties, the melt flow characteristics of the thermoplastic resin change.

  Such a change in melt flow characteristics causes deterioration of the ability of the melt molding material to die during injection molding, resulting in defects such as sink, distortion, warpage, and a change in molding shrinkage. This creates a difference in the finished product dimensions.

  As means for solving the above-mentioned defects, means for increasing the injection filling pressure at the time of injection molding can be considered. However, since the melt flow characteristics of thermoplastic resin change each time it is recycled, new injection molding conditions such as injection molding pressure and injection temperature are newly set each time recycling is performed, and the mold design is also changed. Necessity comes out.

  In order to solve the above-mentioned problems, the present invention provides a gas-assisted process for a recycled thermoplastic resin recovered from a thermoplastic resin waste product or a blend of 1% by mass or more of the recycled thermoplastic resin in a novel thermoplastic resin. Alternatively, the present invention provides a method for producing a recycled thermoplastic resin molded article that is injection-molded by a foam injection molding method.

  Here, the term “waste product” refers to not only used resin molded products collected from the market, but also burrs generated during molding, thermoplastic resin accumulated in sprue and runners, cutting waste generated during trimming, molding defects, and so on. This refers to cutting scraps and defective products generated during assembly of non-defective products and resin products.

  The thermoplastic resins to which the present invention is usefully applied are styrene resins and olefin resins. In addition, when the thermoplastic resin contains a diene rubber and / or an olefin rubber and / or an acrylic rubber, the present invention is more usefully applied.

  In injection-molding the recycled thermoplastic resin or the blend, 1 to 5% by mass of a rubber-like substance compatible with the thermoplastic resin is added to the recycled thermoplastic resin or the blend as a recycling improver. It is desirable.

  When the thermoplastic resin is a styrenic resin, the rubbery material compatible with the styrenic resin includes a diene rubber and / or an olefin rubber and / or an acrylic rubber as a trunk, and a styrenic resin. It is desirable that the polymer be a graft polymer having a polymer chain compatible with the polymer as a graft chain.

  In the case where the thermoplastic resin is an olefin resin, the rubber-like substance compatible with the olefin resin is preferably an ethylene-α-olefin copolymer.

The surface of the thermoplastic resin molded product is coated with a paint and / or ink using a thermoplastic resin or a thermosetting resin compatible with the thermoplastic resin as a vehicle, or the thermoplastic resin. Whether the thermoplastic resin sheet compatible with the thermoplastic resin is bonded to the surface of the molded article with an adhesive made of a thermoplastic resin or a thermosetting resin compatible with the thermoplastic resin, Alternatively, the thermoplastic resin molded article comprises a main part and an attachment part joined to the main part by an adhesive or a welding rod, and the adhesive is a thermoplastic resin compatible with the thermoplastic resin or When the welding rod is made of a thermoplastic resin that is compatible with the thermoplastic resin, the molded product of the thermoplastic resin peels the paint film or ink film. Or removed by, or peeled off sheet, an adhesive or a welding rod without peeled off, can be recycled as it is crushed.
Such a molded product can be pulverized and recycled as it is without sorting.

  In the present invention, during injection molding, the molding material melt adheres well into the mold due to gas pressure or a foaming agent, and the shrinkage of the molded product during cooling is suppressed, resulting in defects such as sink, distortion and warpage. It is possible to obtain a recycled resin molded product having a stable and high product value.

  The thermoplastic resin molded product to be recycled in the present invention is a molded product in which a thermoplastic resin is generally used. For example, a casing or a part of an automobile, a transport machine, an OA device, or a home appliance. Or any molded product such as stationery supplies.

The thermoplastic resin of the thermoplastic resin molded product includes all thermoplastic resins generally used as molding materials.
Examples of such thermoplastic resins include polystyrene (PS), acrylonitrile / butadiene / styrene resin (ABS), acrylonitrile / acrylic rubber / styrene copolymer (AAS, ASA), acrylonitrile / ethylene rubber / styrene copolymer (AES). ), High impact polystyrene (HIPS), acrylonitrile / styrene copolymer (AS), styrene resin such as acrylonitrile / chlorinated polyethylene / styrene copolymer (ACS), polyethylene (PE), polypropylene (PP), ethylene・ Polypropylene copolymers, ethylene-vinyl acetate copolymers (EVA), polyolefin resins such as ionomers, acrylic resins such as polymethyl methacrylate (PMMA) and methyl methacrylate / styrene copolymers, polyvinyl chloride (P A), polyvinylidene chloride, chlorinated vinyl resins such as vinyl chloride-vinylidene chloride copolymer, polycarbonate (PC), polyphenylene ether (PPE), modified polyphenylene ether (modified PPE)
Engineering plastics such as polyetherimide (PEI) and polysulfone (PSF), styrene / butadiene / styrene block copolymer (SBS), styrene / isoprene / styrene block copolymer (SIS), styrene / ethylene / butylene / styrene Styrenic thermoplastic elastomers such as block copolymers (SEBS), styrene / ethylene / propylene / styrene block copolymers (SEPS), thermoplastic polyurethane elastomers, olefinic elastomers, or PP and ethylene / propylene rubber (EPM and / or Or EPDM), polymer alloy of ABS and PC, polymer alloy of HIPS and PC, and polymer alloy of ABS and polybutylene terephthalate (PBT). Roy and the like.

  The thermoplastic resin includes glass fiber, glass bead, carbon fiber, ceramic fiber, metal fiber, mica, talc, calcium carbonate, aluminum silicate, kaolin, silica, calcium metasilicate, bituminous fine powder, zeolite, diatomaceous earth, silica Sand, pumice powder, slate powder, alumina, iron oxide, aluminum sulfate, barium sulfate, lithopone, calcium sulfate, magnesium oxide, molybdenum disulfide, rubber powder, ebonite powder, shellac, wood powder, coconut coconut powder, cork powder, Fillers such as cellulose powder, wood pulp, paper, cloth, mica powder, graphite, glass sphere (GB), volcanic glass hollow body, carbon hollow sphere, anthracite powder, artificial quartz stone, silicone resin fine powder, silica spherical fine particle , Plasticizers, anti-aging agents, UV absorbers, flame retardants, etc. may be added

  The thermoplastic resins to which the present invention is usefully applied include styrene-based resins and olefin-based resins that are generally frequently used for molding. Particularly, the thermoplastic resins to which the present invention is usefully applied include butadiene rubber and isoprene. There are thermoplastic resins including diene rubbers such as rubber and chloroprene rubber, and α-olefin resins.

  Typical thermoplastic resins containing the diene rubber include ABS, HIPS, and modified PPE, and typical α-olefin resins include polypropylene.

  Since the diene rubber contains an unsaturated bond, the unsaturated bond is likely to be broken by heat or mechanical shear force exerted during recycling.

  Further, the α-olefin resin is easily cleaved by a polymer chain due to heat or mechanical shear force exerted upon recycling by the electron excision force of the methyl group at the α-position, and a thermoplastic resin or α containing such a diene rubber. -Olefin resins are likely to be deteriorated in physical properties due to recycling, and melt flow characteristics are likely to change.

  The waste product of the thermoplastic resin molded product is pulverized by a known method and used as a molding material for molding the thermoplastic resin molded product again, or, if desired, the pulverized product is pelletized to obtain a molding material. Is done.

The recycled thermoplastic resin may be mixed with a novel thermoplastic resin to form a molding material. In this case, in order to increase the recycling efficiency, the recycled thermoplastic resin is added to the new thermoplastic resin in an amount of 1% by mass or more, preferably 5% by mass or more. Since the melt flow properties change, the present invention is usefully applied.

[Painting and printing]
The thermoplastic resin molded product may be coated with a paint or may be printed with ink. In this case, it is desirable to use a thermoplastic resin or a thermosetting resin having compatibility with the resin of the molded article as the resin used as the vehicle for the paint or ink.

  In the present invention, “having compatibility” includes a state in which one resin is dispersed in the other resin in a sea-island state and does not cause phase separation other than a state in which the resins are molecularly mixed.

  Examples of the resin compatible with the styrene resin include styrene resin, PPE, modified PPE, PC, and the like. Examples of the resin compatible with PPE or modified PPE include PPE, modified PPE, styrene resin, PC, and the like. Examples of the resin compatible with the olefin resin include olefin resins and halogenated olefin resins.

  In particular, considering the suitability of paints and inks such as solubility in solvents, coating film drying properties, coating workability, and printing workability, styrene-modified acrylic for molded products such as styrene resins, PPE, modified PPE, and PC It is desirable to use paint or ink with resin as vehicle.

  The styrene-modified acrylic resin is a copolymer composed of styrene and an acrylic ester. Examples of the acrylic ester include methyl acrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, and iso-butyl. Examples thereof include acrylates such as acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, and tetrahydrofurfuryl acrylate, and also include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, iso-propyl methacrylate, n-butyl methacrylate, iso- Butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate , Stearyl methacrylate, methacrylate and lauryl methacrylate may be used.

  The styrene-modified acrylic resin is not limited to the compatibility with the molded product, but vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, n-butyl vinyl ether, iso-butyl vinyl ether, acrylonitrile, methacrylo Nitrile monomers such as nitrile, aliphatic vinyls such as vinyl acetate and vinyl propionate, halogen-containing monomers such as vinyl chloride, vinylidene chloride, vinyl fluoride and vinylidene fluoride, olefins such as ethylene and propylene, Dienes such as isoprene, chloroprene and butadiene, α, β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, crotonic acid, atropaic acid and citraconic acid, 2-hydroxyethyl methacrylate, 2-hydroxy D Hydroxyl-containing monomers such as til acrylate, 2-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate and allyl alcohol, amides such as acrylamide, methacrylamide and diacetone acrylamide, dimethylaminomethyl methacrylate, dimethylaminoethyl methacrylate, dimethylamino Amino group-containing monomers such as propyl acrylate, glycidyl acrylate, glycidyl methacrylate, epoxy group-containing monomers such as glycidyl allyl ether, γ-methacryloxypropyltrimethoxysilane, vinylacetoxysilane, p-trimethoxysilylstyrene, p -Triethoxysilylstyrene, p-trimethoxysilyl-α-methylstyrene, p-triethoxysilyl-α-methylstyrene, γ-acryloxy Monomers such as hydrolyzable silyl group-containing vinyl monomers such as propyltrimethoxysilane, vinyltrimethoxysilane, N-β (N-vinylbenzylaminoethyl-γ-aminopropyl) trimethoxysilane, hydrochloride May be copolymerized. In addition, the said monomer may be used individually or in combination of 2 or more types.

  Furthermore, in order to improve the film drying property and film physical properties of the styrene-modified acrylic resin, a fiber derivative is usually added, but the use of a non-yellowing type fiber derivative that does not discolor due to heat of recycling is used. Is desirable.

  Examples of the non-yellowing type fiber derivative include ethyl cellulose, cellulose acetate, benzyl cellulose, cellulose, acetate butyrate and the like.

  The styrene-modified acrylic resin has excellent solubility in solvents, and the solution has low viscosity, no stringing, excellent coating workability, and excellent adhesion to molded products In addition, it is compatible with styrene resin.

  For molded products of olefinic resins, it is desirable to use paints or inks that use halogenated olefinic resins such as chlorinated polypropylene as vehicles.

The halogenated olefin resin exhibits excellent solubility in a solvent, exhibits excellent adhesion to a molded product, and is compatible with the olefin resin.

  Examples of the thermosetting resin include urea resin, melamine resin, urea-melamine cocondensation resin, benzoguanamine resin, phenol resin, resorcinol resin, epoxy resin, thermosetting urethane resin, thermosetting acrylic resin, and melamine-alkyd. There are resins.

  The waste product of the molded product painted or printed with such a paint or ink can be pulverized and recycled as it is without peeling off the coating film.

  In the case of a paint or ink using the above-mentioned compatible resin as a vehicle, the resin is compatible with the resin of the molded product in a molten state without being separated from the resin, so that the physical properties of the regenerated molded product are not deteriorated.

  Also, in the case of paints or inks using the above-mentioned thermosetting resin as a vehicle, the coating film is pulverized together with the molded product waste without being peeled off and dispersed as a filler in the recycled molded product. Does not deteriorate the physical properties of the molded product.

[Composite molded product]
The molded product includes a composite molded product composed of a thermoplastic resin sheet bonded with an adhesive as a label, a seal, or the like, or a main part and an accessory part joined to the main part by an adhesive or a welding rod. .

  Examples of the attachment portion include a frame, a leg portion, a boss, and a label (decal) joined to the main portion.

  In the case of the above-mentioned composite molded product, it is desirable that the main part, the attachment part, the adhesive, or the welding rod is made of a mutually compatible thermoplastic resin, and the thermosetting resin is used as the adhesive. Is also possible.

  For example, a resin compatible with the styrene resin is exemplified by styrene resin, PPE, modified PPE, PC, styrene modified acrylic resin, and the like, which are compatible with PPE or modified PPE. Examples of the resin include PPE, modified PPE, styrene resin, PC, styrene modified acrylic resin and the like, and examples of the resin compatible with the olefin resin include olefin resin and halogenated olefin resin.

  Furthermore, styrene-modified acrylic resins are desirable as adhesives or welding rods for molded products such as styrene-based resins, PPE, modified PPE, and PC.

  The styrene-modified acrylic resin is similar to the styrene-modified acrylic resin used as a vehicle for the paint or ink. When used as an adhesive, the styrene-modified acrylic resin is excellent in solubility in a solvent, and its solution has a low viscosity. Therefore, when used as a welding rod, it is easy to melt, has excellent welding workability, and has excellent adhesion to a molded product.

  The product of the composite molded product composed of the main part, the attachment part, the adhesive, or the thermoplastic resin of the welding rod that is compatible with each other can be pulverized and recycled as it is without being separated.

  Furthermore, it is desirable that the composite molded article is painted or printed with a paint or ink using a resin having compatibility as described above as a vehicle.

  Such waste products of composite molded products can be pulverized and recycled as they are without peeling and separating the coating films.

  Further, when a thermosetting resin is used as the adhesive, it is dispersed in the regenerated molded product as a filler by pulverization, as in the case of paints and inks.

  Even when the thermoplastic resin sheet is bonded to the molded product with an adhesive, the thermoplastic resin of the sheet and the adhesive is selected to be compatible with the thermoplastic resin of the molded product, or as the adhesive, thermosetting A material made of a functional resin is selected.

〔recycling〕
The waste product of the thermoplastic resin molded product is pulverized as described above during recycling. The crushed waste product is injection molded as it is, or the pulverized product is melted by an extruder and extruded into a string shape, cut by a rotary rod and injection molded as a pellet.

Further, as described above, the recycled resin that is the crushed waste product may be mixed with a new thermoplastic resin and injection molded. As described above, the mixing ratio in this case is 1% by mass or more, preferably 5% by mass or more with respect to the new resin.

  When the recycled resin and the new resin are mixed, the new resin powder is mixed with the recycled resin, which is a waste product, and the mixture is injection-molded as it is, or the mixture is pelletized as described above and injection-molded.

  In the recycling, a recycling improver may be added in order to improve the physical properties of the remanufactured product to be produced. The recycling improver will be described below.

[Recycling improver]
The rubber-like substance used as a recycle improver for styrene resin, PPE, modified PPE, and PC is a diene rubber, olefin rubber, or acrylic rubber, and the styrene resin, PPE, modified PPE, It is a graft rubber having a graft chain that is compatible with PC.

  Of the above rubber-like substances, olefin rubber graft polymers and acrylic rubber graft polymers that are particularly excellent in thermal stability are preferred. Hereinafter, each rubber-like substance will be described.

(A: Olefin-based rubber graft polymer)
The olefin rubber used in the recycling improver of the present invention is one or more polymers of α-olefin, or other monomers copolymerizable with one or more of the α-olefins. Copolymers of one or more types, particularly copolymers of ethylene and one or more types of other α-olefins, or other monomers copolymerizable therewith, especially non-conjugated dienes It is a copolymer with a compound.

  In the ethylene-α-olefin copolymer, the α-olefin used as a monomer copolymerized with ethylene is an α-olefin having 3 to 12 carbon atoms, specifically, propylene, butene. -1, 4 methylpentene-1, hexene-1, octene-1, etc.

  Examples of the non-conjugated diene compound include dicyclopentadiene, tricyclopentadiene, 5-methyl-2,5-norbornadiene, 5-methylene-2-norbornene, 5-vinyl-2-norbornene, 5-ethylidene-2-norbornene, 5-isopropylidene-2-norbornene, 5-isopropenyl-2-norbornene, 5- (1-butenyl) -2-norbornene, 5- (2-propenyl) -2-norbornene, 5- (5-hexenyl)- 2-norbornene, 4,7,8,9-tetrahydro-indene, and isopropylidenetetrahydro-indene, cyclooctadiene, vinylcyclohexene, 1,5,9-cyclododecatoluene, 6-methyl-4,7,8, 9-tetrahydroindene, 2,2'-dicyclopentenyl, tiger Su-1,2-divinylcyclobutane, 1,4-hexadiene, 2-methyl-1,4hexadiene, 1,6-octadiene, 1,7-octadiene, 1,8-nonadiene, 1,9-decadiene, 3, Examples include 6-dimethyl-1,7-octadiene, 4,5-dimethyl-1,7-octadiene, 1,4,7-octatriene, 5-methyl-1,8-nonadiene and the like.

  Among these non-conjugated diene compounds, preferred are 5-ethylidene-2-norbornene (ENB) and / or dicyclopentadiene (DCP), more preferably dicyclopentadiene.

  In the olefin rubber graft polymer, the impact strength of the thermoplastic resin for molding can be increased by using EPDM as the main component of rubber rather than EPM.

  Representative examples of the olefin rubber include ethylene / propylene copolymer rubber (EPM), ethylene / propylene / non-conjugated diene compound terpolymer rubber (EPDM), ethylene / butene copolymer rubber (EBM), Butene / non-conjugated diene compound terpolymer rubber (EBDM).

  The non-conjugated diene compound used for the EBDM is the same as that for the EPDM described above.

  Styrene resin in which the olefin rubber is co-mixed with styrene monomer or, in particular, acrylonitrile such as ABS, AAS, ASA, AES, AS, ACS, in order to impart compatibility to the target styrene resin. In this case, a styrene monomer and a nitrile monomer are graft-polymerized.

  Examples of the styrene monomer to be graft-polymerized on the olefin rubber include, for example, styrene, α-alkylmonovinylidene aromatic monomers (for example, α-methylstyrene, α-ethylstyrene, α-methylvinyltoluene, α-methyl). Dialkyl styrene, etc.), ring-substituted alkyl styrene (for example, o, m, or p-vinyl toluene, o-ethyl styrene, p-ethyl styrene, 2,4-dimethyl styrene, p-tertiary butyl styrene, etc.), ring substitution Halostyrene (eg, o-chlorostyrene, p-chlorostyrene, o-promostyrene, 2,4-dichlorostyrene, etc.), ring-alkyl, ring halo-substituted styrene (eg, 2-chloro-4-methylstyrene, 2,6 -Dichlorostyrene, etc.) of styrenic monomers such as vinylnaphthalene and vinylanthracene One kind or a mixture thereof is used.

  Also, generally the alkyl substituent has 1 to 4 carbon atoms and includes both straight and branched alkyl groups.

  Examples of the nitrile monomer that is graft-polymerized to the olefin rubber together with the styrene monomer include acrylonitrile, methacrylonitrile, ethacrylonitrile, fumaronitrile, and mixtures thereof.

  In addition to the styrene monomer and nitrile monomer, other monomers may be copolymerized.

(B: Acrylic rubber graft polymer)
The acrylic rubber used in the present invention is preferably a homopolymer of an acrylate having an alkyl group having 2 to 8 carbon atoms, such as ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, or the like. Non-conjugated diene compounds similar to those used in the above copolymers, or one or more of the above acrylates and butadiene or EPDM, acrylonitrile, methyl methacrylate, vinyl acetate, styrene, ethylene, propylene, etc. Copolymers with one or more monomers, as well as functional monomers such as acrylic acid, methacrylic acid, β-hydroxyethyl methacrylate, acrylamide, dimethylaminoethyl methacrylate, or γ-methacryloxypropyltrimethyl Methoxysila Vinyltriacetoxysilane, p-trimethoxysilylstyrene, p-triethoxysilylstyrene, p-trimethoxysilyl-α-methylstyrene, p-triethoxysilyl-α-methylstyrene, γ-acryloxypropyltrimethoxy It is a copolymer with a polymerizable silane coupling agent such as silane, vinyltrimethoxysilane, N-β (N-vinylbenzylaminoethyl-γ-aminopropyl) trimethoxysilane, hydrochloride.

  Examples of general-purpose acrylic rubber include polyethyl acrylate, poly n-butyl acrylate, n-butyl acrylate-acrylonitrile copolymer, and n-butyl acrylate-butadiene copolymer obtained by copolymerizing some of the above functional monomers. N-butyl acrylate-ethylene copolymer, n-butyl acrylate-γ-methacryloxypropyltrimethoxysilane copolymer, n-butyl acrylate-vinyltrimethoxysilane copolymer, etc. There is an n-butyl acrylate-butadiene copolymer having a molar ratio of n-butyl acrylate / butadiene of 30/70 or more.

  The acrylic rubber is graft polymerized with a styrene monomer or a styrene monomer and a nitrile monomer in the same manner as the olefin rubber, and the heat of styrene resin, PPE resin, or PC resin. Compatibility with the plastic resin is imparted.

  The recycling improver is mixed with the pulverized waste product and injection molded as it is, or mixed with the pulverized waste product and pelletized and injection molded as described above. Is usually about 1 to 10% by mass relative to the pulverized waste product, that is, the recycled resin.

[Other ingredients]
In addition, at the time of recycling, a filler, a plasticizer, an anti-aging agent, an ultraviolet absorber, a flame retardant and the like may be supplemented and added.

[Molding]
In the present invention, the injection molding method is applied to the production of a regenerated molded product.
In order to prevent the occurrence of defects such as sink marks, warpage, distortion, etc., and to prevent the difference in the finished product dimensions by changing the molding shrinkage rate, the molding material melt in the mold cavity A substantially uniform pressure is applied separately from the injection pressure. Such injection molding methods include a gas assist method and a foam injection molding method.

[Foamed injection molding method]
The foam injection molding method includes a chemical foaming method and a mechanical foaming method.
In the chemical foaming method, an injection molding is performed by adding an inorganic and / or organic foaming agent to the thermoplastic resin.

  Examples of the foaming agent include inorganic carbonates such as water, dry ice, sodium bicarbonate, sodium carbonate, and potassium bicarbonate, or acidic carbonates, lithium boron hydrate, sodium boron hydrate, and the like. Examples include hydrogen compounds, nitrites such as ammonium nitrite and sodium nitrite, and combinations of metals and acids or alkalis such as magnesium, aluminum and zinc. Organic compounds include dinitrosopentamethylenenaphthalene, nitrosopentamethylenetetramine, Nitrosomethylene triamine, 2,2'-azobisisobutyronitrile, hydrodicarbonamide, N, N'-dimethyl N, N'-dinitrosotephthalamide, azodicarbonamide, barium azodicarboxylate, paratoluenesulfonyl hydra The 2,4-toluenesulfonyl hydrazide, p-methylurethanebenzenesulfonyl hydrazide, oxalyl hydrazide, p, p'-oxybis (benzenesulfonyl hydrazide), p, p'-oxybis (benzenesulfonyl semicarbazide), p-toluenesulfonyl azide P-toluenesulfonyl semicarbazide, acetone-p-toluenesulfonyl hydrazone, trihydrazine, triazine, acetone-p-toluenesulfonyl hydrazone, N, N′-dimethyl-N, N-dinitrosotephthalamide, diazoaminobenzene, 1, Chemical blowing agents such as azo compounds such as 1'-azobisformamide, nitrourea, nitroguanidine, hydrazine derivatives, semicarbazide compounds, azides, nitroso compounds, triazole compounds, hexa Hydrocarbons such as ethylene, heptane, cyclohexane, octane and gasoline, halogenated hydrocarbons such as dichloroethane and methylene chloride, alcohols such as methanol, ethanol and isopropanol, low boiling solvents such as ethyl ether and methyl ethyl ether, or the above low Examples thereof include foamable capsules in which a boiling point solvent is enclosed in a thermoplastic resin shell.

  In the mechanical foaming method, a gas such as air, nitrogen gas, water vapor, and carbon dioxide gas is mixed with the melt of the molding material. The gas mixing is performed by injecting gas into a molding material melting region in a heating cylinder of an injection molding machine and kneading with a screw or in a nozzle portion at the tip of the heating cylinder.

  In this case, if the pressure and temperature in the heating cylinder are appropriately set, the gas, particularly carbon dioxide gas, can be brought into a supercritical state. However, carbon dioxide gas that has been brought into a supercritical state in advance may be fed into the heating cylinder.

  The supercritical gas can be easily mixed and dissolved in a large amount in the molding material melt, and the supercritical gas can be used as a solvent to improve the fluidity of the molding material melt and injection molding. Improve sex.

  In foam injection molding, as is well known, the molding material melt is injected and filled into the mold cavity while being foamed by the above chemical foaming or mechanical foaming in the heating cylinder of the injection molding machine or in the nozzle portion. As a method, if there is a possibility that gas burning will occur in the molding material by contact with air in advance, a gas such as inert nitrogen gas or carbon dioxide gas is sealed in a mold cavity having an airtight structure. In the gas counter pressure method (GCP), the above-mentioned molding material melt is injected and filled in a foamed state, and the gas is released into the atmosphere during injection or after completion of injection, or during holding or after holding. Law).

  Furthermore, in the present invention, the Ex-cell- ○ method in which the molding material melt is injected into a mold cavity from a plurality of nozzles in a foamed state, the mold cavity can be expanded, and the molding material melt is injected into the cavity. USM (trade name) method in the United States, in which all or part of the cavity is slightly expanded (recessed or recessed) after being injected into the cavity and foamed by lowering the internal pressure of the cavity, or jointly developed by Toshiba Machine and Asahi Dow Foam molding method (TAF (trade name) method), enabling the screw in the heating cylinder to be retracted, injecting the molding material melt into the mold cavity, then retracting the screw by a predetermined amount to lower the cavity internal pressure and foam Allied Chemical's method, US Trexel's Mucel (trade name) process using supercritical carbon dioxide, G developed by Asahi Kasei Corporation Carbon dioxide is used for P, and carbon dioxide is used as a plasticizer for the resin to increase the fluidity of the resin to facilitate filling of the mold with the resin, or to highly transfer the mold surface state to the resin. Product name) is applied.

  Further, in the foam molding, the molding material in the mold is melted and subjected to a foaming pressure such as a decomposition gas pressure of a chemical foaming agent, a vapor pressure of a low boiling point solvent, a gas pressure such as carbon dioxide gas, etc. Also, the shrinkage at the time of cooling the molded product is suppressed by the foamed cells formed inside the molded product, and defects such as sink, distortion and warpage are prevented. The obtained molded product has a skin layer formed on the outer surface in contact with the cavity inner surface, and a foam structure is formed on the inner surface.

[Gas assist method]
The gas assist method (molding material melt) is a method in which a molding material melt is injected into a mold cavity and a gas (gas) such as nitrogen or air is introduced into the cavity in a compressed high pressure state to be molded. , Shaping and holding / cooling with gas.

  The gas assist method includes the following two methods depending on the molding material melt and the injection method and amount of gas.

  One method is that the amount of injection molding material melt is less than the space in the mold cavity (short shot), the gas is introduced outside the injection molding material melt, the melt is delayed by the gas, shaping This method is suitable for molding having a rod-like shape, a thick article, and a large hollow portion. Another method is to inject a molding material melt in an amount substantially equal to the cavity space into the mold (full shot). In a method of introducing a gas into the melt and holding the pressure with the gas, an amount of gas comparable to the volume shrinkage accompanying the cooling and solidification of the molding material melt is injected, which is suitable for molding a thin plate-shaped molded product.

  The position where the gas is pressed into the molding material melt is press-fitted directly into the nozzle of the heating cylinder or the cavity of the mold and through the runner.

As the gas assist method, Asahi Gas Injection (AGI (trade name) method), Running (or RP Topura) Floating of Asahi Kasei Kogyo Co., Ltd.
Core Mold (Molding) (RFM (trade name) method), Gas Press Injection (GPI (trade name) method), High Hollow Mold (Molding) (H2M (trade name) method), Mitsubishi Gas (Gas) Chemical Co., Ltd. Shinpress (trade name) method, GAIN Technology in the US, Batttenfeld Germany air mold method, Contool (trade name) method, Idemitsu Petrochemical Co., Ltd. Gas
Injection Mold (GIM (trade name) method), Nippon Steel Chemical Co., Ltd.'s Partial Frame Process (PFP (trade name) method), and the like are representative, and any of them can be applied to the present invention.

  In addition, a method using a high-pressure liquid instead of the high-pressure gas, for example, a hollow molding method (HELGA (trade name) method) using a liquid that is easily vaporized by Hettinger, Inc. can be applied. Further, in the present invention, for example, a gas assist method can be combined with a foam injection molding method such as the GCP method or a foam injection molding using a supercritical carbon dioxide gas.

  A needle pin is generally used as a means for injecting the high-pressure gas directly into the cavity or into the runner, but a nozzle with a check ball can also be used to prevent gas backflow.

  The tip angle of the needle pin is preferably a sharp shape with an angle smaller than 100 °, and the needle pin has a double cylinder structure in which gas is introduced from the gap between the outer cylinder and the inner cylinder. It is desirable to have a structure to be supplied. The needle pin is easily heated by the molding material melt, and by sharpening the tip of the needle pin, the solidified layer on the surface portion of the molding material melt tends to become thin, and the solidified layer can be easily formed even at a low gas pressure. The gas can be injected into the melt.

  In the gas assist method, by applying a gas pressure to the melt of the molding material in the cavity, defects such as sinks, warpage, and distortion are prevented, and cooling shrinkage is also formed in the molded product. And the occurrence of defects such as sink marks, warpage and distortion is prevented.

  Hereinafter, the present invention will be described by way of an example. In addition, this invention is not limited to the Example shown below.

(Shape of molded product and molded resin)
ABS, HIPS, HIPS (diene rubber-containing) modified PPE is molded to produce a molded product (1) with ribs (3) on one side of the plate (2) shown in FIG. Then, the molded product (1) was pulverized, pelletized, and remolded to produce the molded product (1) shown in FIG. 1 again.

  In the case of the solid (solid) molding and the gas assist method, the shape of the molded product (1) is L = 450 mm, W = 200 mm, t = 3 mm, the height is 15 mm, and the base plate thickness is 2. It has a rib structure in which 6 mm (about 87% of the plate thickness t = 3 mm) ribs (3) are provided at a pitch of 50 mm vertically and horizontally.

  The gate position of the injection molding machine was one side gate, and the size was 3 × 10 mm.

  The shape of the molded product (1) in the case of the foam injection molding method is substantially the same as in the case of the solid molding, and only the plate thickness t is set to 6 mm.

(Solid molding)
In solid molding, injection speed (melting resin filling speed) = 70% and molten resin filling pressure (primary pressure) = 70% to obtain the optimal appearance without sink after completely filling the mold cavity with the molten resin. The secondary pressure (holding pressure) conditions necessary for the test were confirmed.

  As a result, 65% for virgin material, 55% for 1 turn of recycling, 45% for material of 2 turns of recycling, and 45% of material of 3 turns of recycling took 10 seconds, and the molded product was taken out after cooling (set time of cooling = 30 seconds) was completed. .

(Gas assist method)
Immediately after the molten resin is completely filled into the mold cavity at the same filling speed and filling pressure as in the above solid molding (from the completion of the primary pressure, the start of the secondary pressure is 0.5 seconds), and the position indicated by the arrow in FIG. From the gas needle provided, nitrogen was injected into the molded article for 10 seconds at a set pressure of 15 MPa, held for 15 seconds, and then released into the atmosphere. After cooling was completed (cooling setting was 30 seconds, the same as for solid), the molded product was taken out.

  The conditions for gas injection were the same even though the virgin material and the recycled material were the same, because there was no difference in appearance (sink marks).

(Foam injection molding method)
Each of ABS, HIPS, and modified PPE was mixed with 0.2 parts by weight of ADCA (azodicarboxylic amide) and 0.1 part by weight of sodium hydrogen carbonate as a foaming agent to prepare a foamable molding material.

  The foamed molding material is heated and melted in a heating cylinder of an injection molding machine, and the mixed foaming agent is thermally decomposed, while the injection speed is 90% and the filling pressure of the molten resin is 90%. After filling, a secondary pressure (holding pressure) of 60% was applied for 0.5 seconds, and after completion of cooling (cooling set time = 40 seconds), the product was taken out.

  Table 2 shows changes in molding shrinkage when the molded product 1 made of ABS, HIPS, and modified PPE is molded by the solid molding, gas assist method, and foam injection molding method.

  In the case of solid molding, it can be seen that the molding shrinkage rate always changes in any material.

(Painted molded product)
Using a paint mainly composed of a styrene-modified acrylic resin compatible with ABS, HIPS, and modified PPE (the composition of the paint is described in Table 2), the lower surface of the molded product 1 shown in FIG. The coated molded product was pulverized with a coating film, pelletized and remolded, painted again and pulverized, and pelletized and remolded repeatedly.

  Table 3 shows changes in molding shrinkage when the molded article 1 made of ABS, HIPS, and modified PPE is formed by the solid molding, gas assist method, and foam injection molding method.

  In the case of solid molding, it can be seen that the molding shrinkage rate always changes in any material.

(Recover physical properties = Add recycling improver)
For ABS, an olefin rubber graft polymer obtained by graft polymerization of a nitrile monomer and a styrene monomer to an olefin rubber,
For HIPS and modified PPE, an olefin rubber graft polymer obtained by graft polymerization of an olefin rubber with a styrene monomer is used.
The material was added to each of the recycle 1, 2, and 3 turns, and was molded using a material that was intended to recover the physical properties of the material that was reduced by the recycle.

  Table 4 shows changes in molding shrinkage when the molded article 1 made of ABS, HIPS, and modified PPE is formed by the solid molding, gas assist method, and foam injection molding method.

  In the case of solid molding, it can be seen that the molding shrinkage rate always changes in any material.

(Mixed virgin material)
The ABS recycled two-turn material was mixed with the same amount of ABS virgin pellets using a tumbler, and molded using recycled pellets / virgin material = 50/50 mass ratio mixed pellets.

  Table 5 shows the molding shrinkage when the molded product 1 is molded by the solid molding, gas assist method, and foam injection molding method.

  Further, it was molded using a mixed resin of PC / ABS recycled material (recycled material recycled from a market-recovered molded product) / virgin material = 50/50 mass ratio.

  Table 6 shows the molding shrinkage when the molded product 1 is molded by the solid molding and gas assist method.

(adhesive)
AS / Methyl ethyl ketone (MEK) = 20/80 The adhesive (A) dissolved in a mass ratio, similarly the adhesive (B) composed of PS and MEK, and the adhesive (C) containing styrene-modified acrylic resin and MEK as components. ) And manufactured.

The ABS molded article 1 with one turn and the recycled two-turn molded article 1 were bonded using an adhesive (A) or an adhesive (C).
In addition, the HIPS recycled one-turn molded products were bonded to each other using the adhesive (B) and the adhesive (C).

The bonded molded articles were each crushed with an adhesive, pelletized, and molded using a recycled material containing an adhesive.
Table 7 shows the molding shrinkage when the molded product 1 is molded by the solid molding, gas assist method, and foam injection molding method.

(Olefin resin)
Polypropylene (PP) was molded by solid molding and a gas assist method under substantially the same conditions as described above, and a molded product was obtained although some “sinking” was observed.

  Table 8 shows the difference in molding shrinkage when the molded article 1 is repeatedly molded. In the case of solid molding, it can be seen that the molding shrinkage always changes.

(PP recycling improver)
10 parts by mass of ethylene-α-olefin (EPM) as a recycling improver was added to each of the recycled PP materials 1, 2 and 3 and then molded again by solid molding and gas assist method.

  Table 9 shows the difference in molding shrinkage when the molded product 1 is repeatedly molded. In the case of solid molding, it can be seen that the molding shrinkage always changes.

(Welding rods)
Recycled one-turn molded products made of PP were welded to each other by welding a welding rod made of the same PP together with the molded product using a hot dryer.

  The fused molded product was pulverized and pelletized, and molded again by solid molding and a gas assist method. Table 10 shows the difference in molding shrinkage at this time.

(Sprue runner, molding defect)
The sprue runner and the molding failure product generated during the molding of ABS were pulverized, mixed with 20 parts by mass of virgin material, and molded again by solid molding and gas assist method. Table 11 shows the molding shrinkage at this time.

  The sprue runner and the molding failure product generated during the POM molding process were pulverized, mixed with 20 parts by mass of virgin material, and molded again by the gas assist method. Table 12 shows the molding shrinkage at this time.

  In Table 1 and Tables 3 to 12 shown above, each molded product was allowed to stand at room temperature of 23 ° C. for 72 hours, and then measured with a three-dimensional measuring machine to determine a molding shrinkage {molding shrinkage = (actual mold size− Actual size of molded product) / actual size of mold × 1000}.

  As described above, when injection molding is performed using the gas assist method or foam injection molding method, the molding shrinkage rate is constant regardless of the virgin material and the number of recycle turns, and it is not necessary to deal with the difference in mold shrinkage rate depending on the number of recycle turns. It turns out that it becomes.

(Sheet molding)
A resin (AAS) containing 20 MASS% of AnSt-g-AR obtained by graft copolymerizing An and St to AS was extruded at 260 ° C. to obtain a sheet material.

(printing)
The sheet material was printed with a printing ink using a styrene-modified acrylic resin compatible with a styrene resin such as ABS resin as a vehicle to obtain a seal.

(Molding)
A molded article made of ABS was produced.

(Painting)
The molded product surface is coated with a white paint using styrene-modified acrylic resin as a vehicle and titanium oxide as a pigment, and further using the same printing ink as that used for printing the sheet material. Printed on the surface.

(pasting)
The seal was adhered to the surface of the molded article using an adhesive composed of the AnSt-g-AR, a styrene-modified acrylic resin, a plasticizer, and a solvent (ethyl acetate and toluene).

(recycling)
The ABS molded product has a coating film and a printed film, and is provided with a seal, but the molded product is pulverized with the coating film, the printed film and the seal without separating and peeling them. , Pelletized. Then, recycled pellets were obtained from the molded product. When the Izod impact strength of the recycled pellet was measured, the virgin material was 19.7 kg / cm 2, whereas the Izod impact strength of the recycled pellet was reduced to 16.7 kg / cm 2.

(Recover physical properties)
For the purpose of recovering the physical properties of the recycled pellets, AnSt-g-EPDM (wherein D in EPDM is dicyclopentadiene) was added 5 MASS%, and Izod impact strength was measured, and the AnSt-g-EPDM was measured. The Izod impact strength of the recycled pellets to which was added recovered to 20.7 kg / cm 2.

(Molding)
The recycled pellets whose physical properties have been recovered as described above are subjected to general solid molding (solid molding), gas assist molding (gas injection is performed from a sprue runner), foam molding using the GCP method, and GCP method. Molded products were produced by molding by foam molding that was not used. The molding shrinkage rate of the obtained molded product was measured, and the results are summarized in Table 13.

(Painting)
Each of the above-mentioned molded products was painted again, and coating suitability and coating film performance were evaluated. As the evaluation, a normal cross-cut test (primary adhesion) and a cross-cut test (secondary adhesion) performed after the coated molded article was immersed in warm water (40 ° C.) for about 100 hours were performed.

  In addition, since the swirl mark was generated on the surface of the molded product obtained by foam molding without using the GCP method, after the surface was sanded with emery paper (# 380), the effect of the swirl mark was observed for the first time. Undercoating was performed to reduce the size, and then a second coating was applied again.

(Deformation)
As described above, when only the surface of the molded product was coated, the molded product obtained by solid molding was warped and deformed because the internal stress was relaxed by the solvent in the paint. In the molded product obtained by the gas assist method and the foam molding method, it was confirmed that the internal hollow layer and the foam layer absorb the stress of the molded product, there is little residual stress, and there is little warping and deformation by coating.

  An ABS resin with a flammability grade of HB (Psycholac ZFJ5, manufactured by Ube Saikon Co., Ltd.) and an ABS resin with a grade of V0-5V (Psycholac ZFJ15, manufactured by Ube Saikon Co., Ltd.) are respectively molded and processed. A molding material was produced, and the molding material was pulverized to obtain a pulverized material.

  Each grade of pulverized material was mixed and pelletized at a ratio of HB / V0-5V = 25/75, 50/50, 75/25, and the obtained pellets were molded again to form a molded product (A-1 , A-2, A-3) were obtained.

  The molding shrinkage ratio of the obtained molded product was measured by a flammability test method based on 94UL. The measurement results are shown in Table 14.

  On the other hand, the above pulverized materials (HB and V0-5V) are pelletized, and the obtained pellets are mixed at a ratio of HB / V0-5V = 25/75, 50/50, 75/25, and molded and molded. Articles (A-4, A-5, A-6) were obtained. The molding shrinkage of the obtained molded product was measured by the above method. The measurement results are shown in Table 14.

  From the above results, it was confirmed that the molding shrinkage ratio of the molded product obtained by mixing the materials having different flame retardancy was substantially the same as that of the new resin material.

  In addition, there is almost no difference in molding shrinkage between the case where a molded product is manufactured by mixing pulverized materials with different flame retardancy and the case where a molded product is manufactured by mixing pellets with different flame retardancy. Was confirmed.

  ABS resin (Stylac 191 (color: white), manufactured by Asahi Kasei Kogyo Co., Ltd. (hereinafter referred to as 191)) and ABS resin (Techno ABS 170 (color: blue), manufactured by Techno Polymer Co., Ltd. (hereinafter referred to as 170) ) Were respectively injection molded to obtain molded products.

  Each obtained molded product is pulverized, and each pulverized material is mixed and pelletized at a ratio of (191 pulverized material) / (170 pulverized material) = 25/75, 50/50, 75/25. The obtained pellets were molded to obtain molded products (B-1, B-2, B-3).

  The molding shrinkage rate of the obtained molded product (B-1, B-2, B-3) was measured by the above test method. The measurement results are shown in Table 15.

  On the other hand, the above pulverized materials (191 and 170 pulverized materials) were each pelletized, and the obtained pellets were (191 pellets) / (170 pellets) = 25/75, 50/50, 75/25. After mixing and molding, molded products (B-4, B-5, B-6) were obtained.

  The molding shrinkage rate of the obtained molded product (B-4, B-5, B-6) was measured by the test method described above. The measurement results are shown in Table 15.

  From the above results, it is confirmed that the molding shrinkage of molded products obtained by mixing resin manufacturers, grades, that is, materials with different compositions, is approximately the same as the molding shrinkage of molded products obtained from new resin materials. It was.

  In addition, it was confirmed that there was almost no difference in molding shrinkage between the case of producing a molded product by mixing pulverized materials having different compositions and the case of producing a molded product by mixing pellets having different compositions. .

  An ABS resin (Stylac 191) was molded to produce a molding material, and the obtained molding material was pulverized into pellets. The pellets thus obtained were used as recycled one-turn pellets (one-turn pellets). The 1-turn pellet was molded to produce a molding material, and the obtained molding material was pulverized and pelletized.

  The pellets thus obtained were used as recycled 2-turn pellets (2-turn pellets). Thereafter, the same operation was repeated to obtain 3-turn pellets and 4-turn pellets.

  The obtained 1 to 4 turn pellets and the new resin were respectively new resin / 1 turn / 2 turn / 3 turn / 4 turn = 20/20/20/20/20, 10/10/20/30/30 and They were mixed at a ratio of 5/10/25/25/35 and pelletized.

  Molded products (C, D and E) were produced from the obtained pellets, and the molding shrinkage of the molded products was measured. The measurement method was the same as in the above example, and the measurement results are shown in Table 16.

  From the above results, it was confirmed that the molding shrinkage rates of the respective molded products obtained by mixing the materials having different numbers of recycling turns were the same.

Other aspects of the invention are listed below.
(1) Recycled thermoplastic resin recovered from waste thermoplastic resin molded products or a blend of 1% by mass or more of the recycled thermoplastic resin with a new thermoplastic resin is injection molded by a gas assist method or a foam injection molding method. (2) The method for producing a recycled thermoplastic resin molded article according to (1), wherein the thermoplastic resin is a styrene resin (3) The thermoplastic resin is The method for producing a recycled thermoplastic resin molded article according to (1), which is an olefin resin (4) The thermoplastic resin contains diene rubber and / or olefin rubber and / or acrylic rubber (1) To (3) A method for producing a recycled thermoplastic resin molded article (5) In injection molding of the recycled thermoplastic resin or the blend, the recycled thermoplastic resin Alternatively, 1 to 5% by mass of a rubber-like substance compatible with the thermoplastic resin is added to the blend as a recycle improver, and the method for producing a recycled thermoplastic resin molded article according to (1) to (4) (6) The thermoplastic resin is a styrene resin, and the rubber-like substance has a diene rubber and / or an olefin rubber and / or an acrylic rubber as a trunk, and grafts a polymer chain compatible with the styrene resin. (7) The method for producing a recycled thermoplastic resin molded article according to (5), wherein the thermoplastic resin is an olefin resin, and the rubbery substance is an ethylene-α-olefin copolymer (8) A method for producing a recycled thermoplastic resin molded article according to (5), wherein a thermoplastic resin or a thermosetting resin having compatibility with the thermoplastic resin is formed on a surface of the thermoplastic resin molded article. (9) The method for producing a recycled thermoplastic resin molded article according to (1) to (7), wherein a coating material and / or an ink using as a vehicle is applied. A sheet of a thermoplastic resin compatible with the thermoplastic resin is bonded by an adhesive made of a thermoplastic resin or a thermosetting resin compatible with the thermoplastic resin. Method for Producing Recycled Thermoplastic Resin Molded Product (10) The thermoplastic resin molded product comprises a main part and an accessory part joined to the main part by an adhesive or a welding rod, and the adhesive is the thermoplastic. Recycled thermoplastic resin molding according to any one of (1) to (9), wherein the welding rod is made of a thermoplastic resin or thermosetting resin compatible with the resin, and the welding rod is made of a thermoplastic resin compatible with the thermoplastic resin. Manufacturing method

  In the present invention, the injection molding gas pressure during injection molding or the gas pressure generated during decomposition of the foaming agent favorably causes the molding material melt to circulate in the mold, and the shrinkage of the molding during cooling is suppressed. Thus, it is possible to obtain a recycled resin molded product having a stable product size with no defects such as distortion and warpage.

It is a perspective view of the molded product remolded with the recycled resin material which shows one Example of this invention.

Explanation of symbols

1 Molded product 2 Plate 3 Rib 4 Gas inlet

Claims (1)

Recycled thermoplastic resin molding in which a sprue runner and / or defective molding product generated during the molding process of a thermoplastic resin molded product is pulverized and injection molded again using a mixture of the new thermoplastic resin. In the manufacturing method of goods,
Manufacture of recycled thermoplastic resin molded product characterized by molding by gas-assist method under the same molding conditions as molding using new thermoplastic resin even under conditions where melt flow characteristics of said mixture change Method

Images